Rendering a map off-screen

AaronHigh

Hello,

Previously using the ArcGIS WPF Runtime I could create and initialize a map off-screen and render it to a bitmap using RenderTargetBitmap. I'm wondering if there is a preferred method to doing this as I'm currently unable to get a MapView to render unless it's in view, which isn't an option for this use case.

// Sample code

Grid grid = new Grid(){Width=width, Height=height};

Map map = new Map(){Width=width, Height=height};

map.Layers.Add(someLayer);

grid.Children.Add(map);

grid.Measure(new Size(width, height));

grid.Arrange(new Rect(new Size(width, height)));

grid.UpdateLayout();

map.Extent = someExtent;

RenderTargetBitmap rtb = new RenderTargetBitmap(width, height, dpi, dpi, PixelFormats.Default);

rtb.Render(grid);

// Do something with the image here

// End Sample

The sample above is a simplified version of what I'm doing, but the fundamentals are the same. In the .NET 10.2.7 runtime this results in blank images. How can I recreate this behavior in the .NET Runtime? It appears that the map is never initialized unless I bring it into view.

Thanks,

Aaron

AaronHigh

Good Morning Antti,

The basic use case is to provide a secondary "map" that exists on a background thread that can provide images to a proprietary scene rendering engine for use as textures.

BitmapSource PrimaryMap::GetBitmapTexture(Envelope envelope, double imgWidth, double imgHeight)

The key for us here is that the secondary map is able to change extents without impacting the primary map while remaining hidden/off-screen. The secondary map will however always mirror the layers of the primary map.